In U.S. Pat. No. 4,210,258 a seal for plastic buckets and cans is disclosed in which the lip of the bucket and the lid are of a design that permits easy opening, while at the same time avoiding accidental "pop-off" of the lid upon dropping of the bucket, despite the inherently greater flexibility of plastic over the conventional metal cans.
In accordance with this invention, a plastic bucket is provided which can exhibit good resistance to accidental "pop-off" of the lid, while being readily removable by the user, and also where the bucket exhibits exceptional stacking strength so that even though the bucket is made of plastic material, large, heavy, filled buckets of the design of this invention can be stacked six or eight high without distortion or collapse of the lowest bucket in the stack.